Clustered munitions have been used to deliver a variety of war heads, ranging from small field deployed tactical weapons to inter-continental ballistic systems. Tactical systems reside at the conventional end of this class of weapons. The delivery vehicles are customarily referred to as submunitions. Historically submunitions were dispensed in a preselected pattern with or without guidance to control submunition aimpoint.
Wentink, U.S. Pat. No. 4,172,407 on "Submunition Dispenser System" issued Oct. 30, 1979 is exemplary of the early rudimentary submunitions scatter delivery schemes. Obviously such weapon systems are not effective against hard targets such as tanks, armored vehicles or other entities not easily damaged by randomly scattered small munitions. However, hard targets can be destroyed by a direct hit with a shaped charge explosive.
In view of the early shortcomings of ballistic trajectory submunitions such as the Wentink system and the similar Kuesters et al system described in U.S. Pat. No. 4,307,650, improvements have been made to allow guidance of the individual submunitions. One such improvement may be found in the Oglesby et al system presented in U.S. Pat. No. 4,281,809 for "Method Of Precision Bombing" issued Aug. 4, 1981. In this system, a precision guided weapon is launched toward a prime target. The precision guided weapon deploys a plurality of homing beacons which are subsequently tracked by a plurality of inexpensive guided munitions. Such systems still fail to pin point hard targets and are not responsive to moving targets. Therefore, further improvements to missile delivery systems were required.
One attempted improvement is C. Lair et al, U.S. Pat. No. 4,522,356 on "Multiple Target Seeking Clustered Munition And System". This system provides tracking capabilities in the submunitions. Each submunition locks on to the first target of opportunity detected by its guidance systems and tracks and destroys that target. Unfortunately, this system has no means to ascertain if the target happens to have been previously destroyed. Furthermore, the system cannot distinguish between military and civilian targets.
The shortcomings of Lair et al are overcome to a certain extent by the Maudal system for "Sequential Time Discrimination System For Sub-Delivery Systems" of U.S. Pat. No. 4,394,997. This system provides medium range search/seek guidance in the primary delivery vehicle combined with a short range starting seeker and ejector system which attempts to prevent the submunitions from tracking previously destroyed targets.
The identification problem is to find a true target in the presence of high clutter. Previous art required targets to be resolved with high contrast without regard to the background, which, unfortunately, was frequently not met in real world conditions.
K. Eichweber in U.S. Pat. No. 4,004,487 for "Missile Fire Control System And Method" issued Jan. 25, 1977 attempts to solve the target recognition problem for clustered munitions by providing a means whereby an operator may view the target area and designate targets for the individual submunitions. This is a costly system requiring operators to be actively engaged in weapon system guidance up to the final second and therefore subject to failure due to the vulnerability of the operators.
G. Tisdale et al, U.S. Pat. No. 4,497,065 on "Target Recognition System Enhanced By Active Signature Measurements" and the Grumet system in U.S. Pat. No. 3,779,492 on "Automatic Target Recognition System" are examples of recognition systems which allow weapon guidance systems to recognize a specific type of target from among a clutter of possible targets and home on the selected target. But the state of the art of such systems does not have the capability of assigning independent priorities for various submunitions of a clustered system. Therefore their use in such a clustered system would result in plural munitions descending on a common target.
All of the previous systems incorporate expensive guidance systems usually incorporating inertial platforms relying on costly gyros which nevertheless fail to hit the target due to false alarms from clutter. This has effectively limited progress on autonomously guided submunition systems.
There is, therefore, a need for an improved target acquisition system which will overcome the above limitations and disadvantages particularly in eliminating the effects of false alarms without reducing the potential capability of identifying all true targets.